Apparatus and method for manufacturing cutting inserts

ABSTRACT

A method for manufacturing a cutting insert green body from a sinterable powder, a tool set for manufacturing the cutting insert green body by that method and the green body manufactured by the tool set. The tool set has axially moving upper and lower punches and radially moving side punches. The side punches move slidably on die rods. The side punches and die rods move in channels in a base body on which a cover plate is mounted. The upper and lower punches move in through holes in the cover plate and base body, respectively. The die rods are stationary during compaction of the sinterable powder. The upper, lower and side punches form surfaces of the green body and the die rods form some of the edges of the green body. The green body can have undercuts and the edges formed by the die rods can be non-linear in shape.

RELATED APPLICATIONS

This is a Divisional of U.S. patent application Ser. No. 13/445,674,filed 12 Apr. 2012, now U.S. Pat. No. ______, which claims priority toIL 214642, filed 14 Aug. 2011. The contents of the aforementionedapplications are incorporated by reference in their entirety. Thesubject matter of the present application is related to commonly ownedU.S. patent application Ser. No. 13/341,768, filed 30 Dec. 2011.

FIELD OF THE INVENTION

The subject matter of the present application relates to a method andapparatus for manufacturing pre-sintered cutting insert green bodies, tobe subsequently sintered into cutting inserts.

BACKGROUND OF THE INVENTION

Fabrication of cutting inserts from sinterable powders, i.e.,metallurgical, cermets or ceramics powders, comprises compaction of thesinterable powder, with or without a fugitive binder, into apre-sintered green body, and subsequent sintering of the green body toproduce a cutting insert. Compaction generally takes place under highpressures obtained through large opposing forces generated by a systemof punches in a die. For example, by upper and lower punches urgedtowards a die cavity formed in a die containing the sinterable powder,as is well known in the art. Although cutting inserts having undercutfeatures may generally be pressed, these features may inhibit releaseand subsequent extraction of the compacted green body from the diecavity.

It is the object of the present invention to provide a new and improvedapparatus and method for manufacturing pre-sintered cutting insert greenbodies.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the subject matter of the presentapplication, there is provided a tool set configured to compact asinterable powder to form a green body. In general, the sinterablepowder can include a binder. The green body can be a cutting insertgreen body and after compaction the green body can be sintered toproduce a cutting insert.

The tool set has a central axis which defines a reference axialdirection. Radial directions are defined perpendicular to the centralaxis. The tool set comprises a base body having a base through hole, aplurality of radially directed punch channels, a plurality of radiallydirected die channels and a cover plate mountable on the base body. Thecover plate has a plate through hole and the central axis passes throughthe base and plate through holes when the cover plate is mounted on thebase body.

The tool set also comprises an upper punch, an opposing lower punch, aplurality of side punches and a plurality of die rods. The upper punchis axially moveable through the plate through hole and the lower punchis axially moveable through the base through hole. The side punches arearranged in opposing pairs of side punches, and are radially moveable inthe punch channels. The die rods are radially moveable in the diechannels. Each die rod is common to and located between two adjacentside punches. Each die rod has a forward die shaping surface and two dieguiding surfaces on which the two adjacent side punches are slidablymoveable. The die guiding surfaces diverge rearwardly from the dieshaping surface.

In accordance with the subject matter of the present application, thetool set is configured to be adjusted from a first configuration priorto compaction of the sinterable powder to a second configuration aftercompaction of the sinterable powder. In the first configuration, theupper, lower and side punches form an initial closed cavity. The initialclosed cavity may contain non-compacted sinterable powder. In the secondconfiguration the upper lower and side punches and the die rods form afinal closed cavity. The final closed cavity may contain compactedsinterable powder.

The upper, lower and side punches have, respectively upper, lower andside punch faces and the final closed cavity may be bounded by theupper, lower and side punch faces and by the die rod shaping surface.

In the first configuration the side punches are in a first positionremote from the base through hole and in the second configuration theside punches are in a second position adjacent the base through hole.The arrangement being such that the die rods are located adjacent thebase through hole in both the first and second configurations.

Compaction of the sinterable powder to form the green body may beeffected by moving the upper and lower punches towards each other and bymoving the side punches from the first position to the second positionduring which the die rods remain stationary adjacent the base throughhole and the side punches move slidably on the die guiding surfaces.This arrangement is advantageous in that it ensures that the sidepunches will be guided to precise positions on either side of therespective die rods on the completion of the compaction of thesinterable powder.

In accordance with aspects of the subject matter of the presentapplication, the die shaping surfaces of the die rods form minor edgesof the green body. The die shaping surface can have any desired shape.The use of a die shaping surface provides a larger degree of freedom inthe shapes of green body edges that can be manufactured in comparisonwith green body edges manufactured by prior art compaction tool sets.

In accordance with a specific embodiment of the subject matter of thepresent application, each minor edge comprises two minor cutting edgesand in an end view of the green body the two minor cutting edges arenon-collinear. In accordance with this specific embodiment, each minoredge is nonlinear in shape. Since the minor edge is formed by the dieshaping surface, the die shaping surface will also be nonlinear inshape.

In accordance with a further specific embodiment of the subject matterof the present application, the green body comprises two opposing sidesurfaces and a peripheral surface extending between the two opposingside surfaces. The peripheral surface may comprise four identical endsurfaces. Adjacent end surface may intersect at the minor edge.

In accordance with yet a further specific aspect of the subject matterof the present application, each side punch may have a protruding sidepunch face and the green body may have recessed end surfaces. Therecessed end surfaces are formed by the protruding side punch facesduring compaction of the sinterable powder.

In accordance with aspects of the subject matter of the presentapplication, the upper punch has an upper punch face and the lower punchhas a lower punch face, and the upper and lower punch faces form theside surfaces of the green body during compaction of the sinterablepowder.

In accordance with a further aspect of the subject matter of the presentapplication, there is provided a method for manufacturing a green body,the method comprising the steps of providing a tool set in accordanceaspects of the subject matter of the present application as describedhereinabove; establishing an initial closed cavity between the upper andlower punches, the side punches and the die rods, with a predeterminedamount of sinterable powder located in the initial closed cavity;deriving a final closed cavity from the initial closed cavity by urgingthe upper and lower punches towards each other and by urging the sidepunches of opposing pairs of side punches towards each other with eachtwo adjacent side punches moving slidably on the die guiding surfaces ofthe common die rod whilst maintaining the die rods stationary withrespect to the side punches thereby compacting the sinterable powder toform the green body. To remove the green body the tool set is brought toa removal configuration by removing the upper punch and the cover platefrom the base body, withdrawing the die rods and the side punches to aposition remote from the green body and bringing the lower punch to alower punch removal position wherein the lower punch protrudes from thebase through hole thereby enabling removal of the green body.

In accordance with some embodiments, the method comprises the furtherstep of producing a through bore in the green body.

The tool set may comprise a center pin in order to produce the throughbore.

In accordance with yet a further aspect of the subject matter of thepresent application, there is provided a green body manufactured inaccordance with the method of manufacture described above. The greenbody manufactured by this method, may comprise two opposing sidesurfaces and a peripheral surface extending between the two opposingside surfaces. The peripheral surface may comprise four identical endsurfaces. Each end surface may extend between two adjacent end surfaces.

In accordance with some aspects of the present application, each endsurface and each side surface may intersect at a major edge. At least aportion of the major edge may form a major cutting edge. Adjacent endsurfaces may intersect at a minor edge. The minor edge may comprise twominor cutting edges.

In accordance with a specific embodiment of the present application, theend surfaces may be recessed.

In accordance with another specific embodiment of the presentapplication, in an end view of the green body the two minor cuttingedges may be non-collinear.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show how thesame may be carried out in practice, reference will now be made to theaccompanying drawings, in which:

FIG. 1 is a perspective view of a green body manufactured in accordancewith a method of the present invention;

FIG. 2 is a side view of the green body shown in FIG. 1;

FIG. 3 is an end view of the green body shown in FIG. 1;

FIG. 4 is a perspective view of a tool set in accordance with thepresent invention;

FIG. 5 is an exploded perspective view of the tool set of FIG. 4;

FIG. 6 is a partial view of the tool set in an open configuration;

FIG. 7 is a partial view of the tool set in a closed configuration; and

FIG. 8 is a partial view of the tool set in a removal configuration.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, various aspects of the subject matter ofthe present application will be described. For purposes of explanation,specific configurations and details are set forth in sufficient detailto provide a thorough understanding of the subject matter of the presentapplication. However, it will also be apparent to one skilled in the artthat the subject matter of the present application can be practicedwithout the specific details presented herein.

Attention is drawn to FIGS. 1 to 3 showing a nonbinding example of apre-sintered cutting insert green body 10 formed by compaction of asinterable powder in accordance with aspects of the subject matter ofthe present application. Sintering the green body 10 results in acutting insert. The cutting insert may be used in metal cuttingoperations. The sinterable powder may be a metallurgical, ceramic orcermet powder mixed with a binder. The green body 10 has two opposingside surfaces 12 and a peripheral surface 14 extending therebetween. Thegreen body 10 may have a through bore 16. The through bore 16 may extendbetween the side surfaces 12. The through bore 16 has a bore axis Babout which the green body 10 may have 90° rotational symmetry. Theperipheral surface 14 has four identical end surfaces 18 which face infour different directions. The end surfaces 18 may be recessed, therebydefining an undercut geometry. Each end surface 18 and each side surface12 intersect at a major edge 20. Each end surface 18 has two major edges20 and the green body 10 has a total of eight major edges 20. At least aportion of each major edge 20 forms a major cutting edge 22. Each majorcutting edge 22 may extend over more than half the length of the majoredge 20 on which it is formed.

Adjacent end surfaces 18 intersect at a minor edge 24. The minor edge 24includes exactly two minor cutting edges 26 connected by an intermediateminor edge 28. The major cutting edges 22 are longer than the minorcutting edges 26. Each minor cutting edge 26 has an adjacent majorcutting edge 22. Adjacent major and minor cutting edges 22, 26 have anassociated corner cutting edge 30 that extends between the adjacentmajor and minor cutting edges 22, 26. In other words, adjacent major andminor cutting edges 22, 26 merge at a corner cutting edge 30. Eachtriplet of adjacent major and minor cutting edges 22, 26 and associatedcorner cutting edge 30 forms an insert cutting edge 32.

Each insert cutting edge 32 is formed at the intersection of twosurfaces located on either side of the cutting edge 32. One surface is arake surface 34, located in an end surface 18 and the other surface is arelief surface 36. The relief surface 36 associated the major cuttingedge 22 is located in a side surface 12. The relief surface 36associated the minor cutting edge 26 is located in an end surface 18 andthe relief surface 36 associated the corner cutting edge 30 is locatedin a corner surface located between the side surface 12 and the endsurface 18. Therefore, each triplet of major, minor and corner cuttingedges 22, 26, 30 of a given insert cutting edge 32 is associated with aspecific rake surface 34 and a specific relief surface 36, namely therake surface 34 and relief surface 36 at the intersection of which theinsert cutting edge 32 is formed. The rake surface 34 may extend fromthe insert cutting edge 32 in an inward direction of the green body 10.The rake surface 34 may extend towards an inner end surface 38 of theend surface 18. In accordance with some applications, the rake surface34 extends to the inner end surface 38 of the end surface 18. One of thetwo minor cutting edges 26 belongs to one of the adjacent end surfaces18 and the other one of the two minor cutting edges 26 belongs to theother one of the adjacent end surfaces 18. Stated another way, one ofthe two minor cutting edges 26 of a given minor edge 24 is associatedwith a rake surface 34 in one end surface 18 and the other minor cuttingedge 26 of the given minor edge 24 is associated with a rake surface 34in an adjacent end surface 18.

As can be seen in FIG. 2, in a side view of the green body 10 the twoside surfaces 12 are not aligned with each other but are rotatedrelative to one another about the bore axis B by a non-zero angle α. Ascan be seen in FIG. 3 in an end view of the green body 10 adjacent minorcutting edges 26, that is, minor cutting edges 26 located on a commonminor edge 24, are spaced from each other by a distance d. Consequently,in an end view of the green body 10 the two minor cutting edges 26formed on a common minor edge 24 are non-collinear. Moreover, the twominor cutting edges 26 and intermediate minor edge 28 formed on a commonminor edge 24 are non-collinear.

Attention is now drawn to FIGS. 4 to 8 showing a tool set 40. The toolset 40 may be configured to compact a sinterable powder into the greenbody 10 shown in FIGS. 1 to 3. The tool set 40 has a central axis Awhich defines a reference axial direction. Radial directions are definedperpendicular to the central axis A. The tool set 40 may include a basebody 42 on which a cover plate 44 is mountable. The cover plate 44 mayhave the form of a flat plate, for example a disc, and has a platethrough hole 46 extending therethrough. The base body 42 is bounded byan outer base peripheral surface 48 and an inner base through hole 50.When the cover plate 44 is mounted on the base body 42 the central axisA passes through the plate and base through holes 46, 50. The base body42 may have a plurality of radially directed punch channels 52 and aplurality of radially directed die channels 54. The punch channels 52and the die channels 54 are arranged alternatingly and extend from thebase peripheral surface 48 to the base through hole 50. The punch anddie channels 52, 54 may be elongated in form. In accordance with someapplications the base body 42 may have four radially directed punchchannels 52, and four radially directed die channels 54.

The tool set 40 has an upper punch 56, an opposing lower punch 58 andside punches 60 for compacting the sinterable powder into the green body10. The upper and lower punches 56, 58 are configured and dimensioned tobe slidingly received in the plate through hole 46 and base through hole48, respectively. The side punches 60 are configured and dimensioned tobe slidingly received in respective punch channels 52. In accordancewith some applications there may be four side punches 60.

The upper and lower punches 56, 58 and the side punches 60 may have anelongated rod-like structure, each having at one end a punch faceconfigured to come into contact with and compact the sinterable powderinto the green body 10. The upper punch 56 has an upper punch face 62,the lower punch 58 has a lower punch face 64 and each side punch 60 hasa side punch face 66. The upper punch face 62 is bounded by an upperpunch peripheral edge 68, the lower punch face 64 is bounded by a lowerpunch peripheral edge 70 and each side punch face 66 is bounded by aside punch peripheral edge 72. Each punch face is configured to form asurface of the green body 10. The upper and lower punch peripheral edges68, 70 can have upper and lower punch peripheral corner edges 68′, 70′,respectively, at corners of the upper and lower punch faces 62, 58. Thetool set 40 also has die rods 74. Each die rod 74 has at one end a diefront surface 76 comprising a forward die shaping surface 78 bounded bya die rod peripheral edge 80 and two die guiding surfaces 82 thatdiverge rearwardly from the die shaping surface 78. The die rodperipheral edge 80 can have die rod peripheral corner edges 80′ atcorners of the die shaping surface 78. The die shaping surface 78 ofeach die rod 74 is configured to form an edge of the green body 10 andthe die guiding surfaces 82 are configured to guide adjacent sidepunches 60 during compaction of the sinterable powder. The die rods 74are configured and dimensioned to be slidingly received in respectivedie channels 54. Each side punch 60 is located between two die rods 74and conversely, each die rod 74 is located between two side punches 60.The die rods 74 may have an elongated rod-like structure. In accordancewith some applications there may be four die rods 74.

In accordance with the specific application in which tool set 40 isconfigured to form the pre-sintered cutting insert green body 10, shownin FIGS. 1 to 3, the upper and lower punch faces 62, 64 face each otherand are configured to form the side surfaces 12 of the green body 10.The side punch faces 66 are configured to form the end surfaces 18 ofthe green body 10. The die shaping surface 78 of each die rod 74 isconfigured to form a minor edge 24 of the green body 10. A center pin 84may be used for producing the through bore 16 during the compaction ofthe green body 10. The center pin 84 may be located on the lower punch58 and may extend in a direction towards the upper punch face 62.

The upper and lower punches 56, 58 are axially moveable along thecentral axis A. The upper punch 56 is axially moveable through the platethrough hole 46, the lower punch is axially moveable through the basethrough hole 50, the side punches 60 are radially moveable in the punchchannels 52 and the die rods 74 are radially moveable in the diechannels 64. The side punches 60 and the die rods 74 are radiallydisplaced from the central axis A and are disposed axially between theupper and lower punches 56, 58. The four side punches 60 may be arrangedin two opposing pairs, first and second opposing pairs 60A1, 60A2, withthe first opposing pair 60A1 moveable along a radially directed firstside axis A1 and the second opposing pair 60A2 moveable along a radiallydirected second side axis A2. The first axis A1 may be perpendicular tothe central axis A. The second axis A2 may be perpendicular to thecentral axis A. The first and second axes A1, A2 may be perpendicular toeach other.

To manufacture the green body 10, the tool set 40 may be cycled througha number of configurations which may include, for example, an openconfiguration, a compaction configuration, a closed configuration and aremoval configuration. In the open configuration the tool set 40 mayhold the sinterable powder. In the compaction configuration the tool set40 may be ready for compacting the sinterable powder. The closedconfiguration is the state of the tool set 40 after compaction of thesinterable powder. In the removal configuration of the tool set 40 thegreen body 10 may be removed from the tool set 40.

The compaction stages during the manufacture of the green body 10 may beassociated with two configurations of the tool set 10. A firstconfiguration, prior to compaction, corresponds to the compactionconfiguration and a second configuration, after compaction, correspondsto the closed configuration.

FIG. 6 shows a partial view of the tool set 40 in an open configuration.FIG. 6 is a partial view for reasons of clarity so that the positions ofthe side punches 60 (only two shown) relative to the die rods 74 (onlyone shown) can be clearly seen. In the open configuration the sidepunches 60 are located in the punch channels 52, the die rods 74 arelocated in the die channels 54 and the lower punch 58 is located in thebase through hole 50. Not seen in FIG. 6 are the upper punch 56 andcover plate 44 which are spaced apart from the base body 42 in the openconfiguration. Each die rod 74 is located in a die rod final position.In the die rod final position the die shaping surface 78 of each die rod74 is located adjacent the base through hole 50. The die rod finalposition is the position of the die rods 74 during compaction of thesinterable powder. The lower punch 58 is located in the base throughhole 50 in a lower punch initial position. In the lower punch initialposition the lower punch 58 is located in the base through hole 50 butdoes not completely fill the base through hole 50. That is, the basethrough hole 50 is partially exposed. The side punches 60, the die rods74 and the lower punch 58 form an open cavity OC of the tool set 40. Theopen cavity OC may hold the sinterable powder.

In accordance with some embodiments, in the open configuration, eachside punch 60 is located between two die rods 74 in a side punch initialposition. In the side punch initial position each side punch 60 may bein contact with the die guiding surfaces 82 of adjacent die rods 74. Inthe side punch initial position the side punches 60 are radially offset,or remote, from the base through hole 50 and the die rods 74 areadjacent the base through hole 50. The side punch initial position willalso be referred to herein as a first position of the side punch 60.

The compaction configuration of the tool set 40 may be obtained from theopen configuration by placing the cover plate 44 on the base body 42with the upper punch 56 located in the plate through hole 46 as shown inFIG. 4. In the compaction configuration the upper punch 56 is located inan upper punch initial position. In the upper punch initial position theupper punch 56 is located at least partially in the plate through hole46 and the upper punch 56 is spaced apart from the side punches 60. Inthe compaction configuration the presence of the cover plate 44 andupper punch 56 turns the open cavity OC into an initial closed cavityICC. Since the compaction configuration may be obtained from the openconfiguration, the arrangement of the side punches 60, die rods 74 andlower punch 58 in the compaction configuration is as shown in FIG. 6.The arrangement of the upper punch 56 is as described herein above. Theinitial closed cavity ICC is indicated in FIG. 6 in which the upperpunch 56 is not shown. The initial closed cavity ICC is formed by thedie rods 74 and the upper, lower and side punches 56, 58, 60.

In embodiments in which the tool set 40 is configured to compact thegreen body 10 shown in FIGS. 1 to 3, the upper and lower punches 56, 58are rotated relative to one another about the central axis A by an angleα. This arrangement ensures that the upper and lower punch faces 62, 64are rotated relative to one another about the central axis A by an angleα so that the two side surfaces 12 of the green body 10 will be rotatedrelative to one another about the bore axis B by the angle α.

FIG. 7 shows a partial view of the tool set 40 in a closedconfiguration. FIG. 7 is a partial view for reasons of clarity. Theupper punch is not shown so that the positions of the side punches 60(only two shown) relative to the doe rods 74 (only one shown) and thelower punch 58 can be clearly seen. In the closed configuration, eachdie rod 74 is located in the die rod final position, and the upper,lower and side punches 56, 58, 60 are located, respectively, in upper,lower and side punch final positions. The closed configuration may beobtained from the compaction configuration urging the upper and lowerpunches 56, 58 towards each other and by urging the opposing pairs ofside punches 60A1, 60A2 towards each other. As the side punches 60 movetowards each other they slide on adjacent die guiding surfaces 82 whichguide each side punch 60 to the side punch final position. The sidepunch final position will also be referred to herein as a secondposition of the side punch 60.

In the closed configuration, the die rods 74 and the upper, lower andside punches 56, 58, 60 form a final closed cavity FCC. The final closedcavity FCC is bounded by the upper, lower and side punch faces 62, 64,66 and by the die shaping surfaces 78. In the closed configuration, theside punch peripheral edges 72 are in contact with adjacent die rodperipheral edges 80 and the upper and lower punch peripheral edges 68,70 are in contact with adjacent side punch peripheral edges 72. Theupper and lower punch peripheral corner edges 68′, 70′ are in contactwith respective die rod peripheral corner edges 80′. The side punch anddie rod peripheral edges 72, 80 that are in contact with each other areshaped to have matching geometries so that they fit together with nogaps between them. Similarly, the upper and lower punch peripheral edges68, 70 and the side punch peripheral edges 72 that are in contact witheach other are also shaped to have matching geometries so that they alsofit together with no gaps between them.

In the side punch final position, the side punches are adjacent the basethrough hole 50 with the side punch peripheral edges 72 in contact withadjacent die rod peripheral edges 80. In the lower punch final positionthe lower punch 58 is located in the base through hole 50 completelyfilling the base through hole 58. That is, none of the base through hole50 is exposed. The final closed cavity FCC is smaller than the initialclosed cavity ICC. The final closed cavity FCC forms the shape of thegreen body 10. In the closed configuration, the die shaping surfaces 78the upper, lower and side punch faces 62, 64, 66 are in contact withrespective surfaces of the green body 10.

The removal configuration is shown in FIG. 8. The removal configurationmay be obtained from the closed configuration by removing the upperpunch 56 and cover plate 44, by withdrawing the die rods 74 to a die rodremoval position and by withdrawing the side punches 60 to a side punchremoval position. In the die rod and side punch removal positions, thedie rods 74 and the side punches 60 are no longer adjacent the basethrough hole 50 and no longer engage the green body 10. In other words,in the removal configuration the die rods 74 and the side punches 60 arein a position remote from the green body 10. After bringing the die rods74 and the side punches 60 to the die rod and side punch removalpositions the lower punch 58 is moved to a lower punch removal position.In the lower punch removal position, the lower punch 58 protrudes fromthe base through hole 50 (see FIG. 8) and the green body 10, which islocated on the lower punch face 64 can easily be removed from the toolset 40.

A method for manufacturing a green body, for example green body 10 shownin FIGS. 1 to 3, comprises a number of steps in which the configurationof the tool set 40 is altered so that sinterable powder can beintroduced into the tool set 40, compacted into the green body 10 andthen removed from the tool set 40. For example, one step may involveestablishing an initial closed cavity (ICC) between the upper and lowerpunches (56, 58), the side punches (60) and the die rods (74), with apredetermined amount of sinterable powder located in the initial closedcavity (ICC). Another step may involve deriving a final closed cavity(FCC) from the initial closed cavity (ICC) by urging the upper and lowerpunches (56, 58) towards each other and by urging the side punches (60)of opposing pairs of side punches (60) towards each other with each twoadjacent side punches (60) moving slidably on the die guiding surfaces(82) of the common die rod (74) whilst maintaining the die rods (74)stationary with respect to the side punches (60) thereby compacting thesinterable powder to form the green body (10) A final step may involvebringing the tool set (40) to a removal configuration by removing theupper punch (56) and the cover plate (44) from the base body (42),withdrawing the die rods (74) and the side punches (60) to a positionremote from the green body (10) and bringing the lower punch (58) to alower punch removal position wherein the lower punch (58) protrudes fromthe base through hole (50) thereby enabling removal of the green body(10).

Although the present invention has been described to a certain degree ofparticularity, it should be understood that various alterations andmodifications can be made without departing from the scope of theinvention as hereinafter claimed.

What is claimed is:
 1. A method for manufacturing a green body (10) comprising the steps of: (i) providing a tool set (40) having a central axis (A) defining axial and radial directions, and comprising: a base body (42) having a base through hole (50), a plurality of radially directed punch channels (52) and a plurality of radially directed die channels (54); a cover plate (44) mountable on the base body (42), the cover plate (44) having a plate through hole (46), the central axis (A) passing through the base and plate through holes (50, 46) when the cover plate (44) is mounted on the base body (42); an upper punch (56) and an opposing lower punch (58), the upper punch (56) being axially moveable through the plate through hole (46), the lower punch (58) being axially moveable through the base through hole (50); a plurality of side punches (60) arranged in opposing pairs, the side punches being radially moveable in the punch channels (52); and a plurality of die rods (74) radially moveable in the die channels (54), each die rod (74) being common to and located between two adjacent side punches (60), each die rod (74) having a forward die shaping surface (78) and two die guiding surfaces (82) diverging rearwardly therefrom; wherein the two adjacent side punches (60) are slidably moveable on the die guiding surfaces (82) of the common die rod (74). (ii) establishing an initial closed cavity (ICC) between the upper and lower punches (56, 58), the side punches (60) and the die rods (74), with a predetermined amount of sinterable powder located in the initial closed cavity (ICC); (iii) deriving a final closed cavity (FCC) from the initial closed cavity (ICC) by urging the upper and lower punches (56, 58) towards each other and by urging the side punches (60) of opposing pairs of side punches (60) towards each other with each two adjacent side punches (60) moving slidably on the die guiding surfaces (82) of a common die rod (74) whilst maintaining the die rods (74) stationary with respect to the side punches (60) thereby compacting the sinterable powder to form the green body (10); and (iv) bringing the tool set (40) to a removal configuration by removing the upper punch (56) and the cover plate (44) from the base body (42), withdrawing the die rods (74) and the side punches (60) to a position remote from the green body (10) and bringing the lower punch (58) to a lower punch removal position wherein the lower punch (58) protrudes from the base through hole (50) thereby enabling removal of the green body (10).
 2. The method according to claim 1, further comprising the step of producing a through bore (16) in the green body (10).
 3. A method for manufacturing a cutting insert comprising the steps of: (a) manufacturing a green body (10) in accordance with claim 1; and (b) sintering the green body (10).
 4. A green body (10) manufactured according to the method of claim 1, the green body (10) comprising: two opposing side surfaces (12) and a peripheral surface (14) extending therebetween, the peripheral surface (14) comprising four identical end surfaces (18), each end surface (18) extending between two adjacent end surfaces (18); each end surface (18) and each side surface (12) intersect at a major edge (20), at least a portion of the major edge (20) being a major cutting edge (22); and adjacent end surfaces (18) intersect at a minor edge (24), the minor edge (24) comprising two minor cutting edges (26).
 5. The green body (10) according to claim 4, wherein the end surfaces (18) are recessed.
 6. The green body (10) according to claim 5, wherein in an end view of the green body (10) the two minor cutting edges (26) are non-collinear.
 7. The green body (10) according to claim 4, wherein in an end view of the green body (10) the two minor cutting edges (26) are non-collinear.
 8. The green body (10) according to claim 4, wherein: in an end view of the green body (10) the two minor cutting edges (26) are non-collinear; in a side view of one of the side surfaces (12), the green body has a through bore (16) having a bore axis (B) about which the green body has rotational symmetry; and the two opposing side surfaces (12) are rotated relative to one another about the bore axis (B) by a non-zero angle (α).
 9. The green body (10) according to claim 8, wherein: the minor edge (24) further comprises an intermediate edge (28) between the two minor cutting edges (26); and in an end view, the two minor cutting edges (26) and the intermediate minor edge (28) formed on a common minor edge (24) are non-collinear.
 10. The green body (10) according to claim 4, wherein: the end surfaces (18) are recessed; in an end view of the green body (10) the two minor cutting edges (26) are non-collinear; in a side view of one of the side surfaces (12), the green body has a through bore (16) having a bore axis (B) about which the green body has rotational symmetry; the two opposing side surfaces (12) are rotated relative to one another about the bore axis (B) by a non-zero angle (α); the minor edge (24) further comprises an intermediate edge (28) between the two minor cutting edges (26); and in an end view, the two minor cutting edges (26) and the intermediate minor edge (28) formed on a common minor edge (24) are non-collinear.
 11. A method for manufacturing a cutting insert comprising the steps of: (a) providing a green body (10) comprising: two opposing side surfaces (12) and a peripheral surface (14) extending therebetween, the peripheral surface (14) comprising four identical end surfaces (18), each end surface (18) extending between two adjacent end surfaces (18); each end surface (18) and each side surface (12) intersect at a major edge (20), at least a portion of the major edge (20) being a major cutting edge (22); adjacent end surfaces (18) intersect at a minor edge (24), the minor edge (24) comprising two minor cutting edges (26); wherein: the end surfaces (18) are recessed; in an end view of the green body (10) the two minor cutting edges (26) are non-collinear; in a side view of one of the side surfaces (12), the green body has a through bore (16) having a bore axis (B) about which the green body has rotational symmetry; the two opposing side surfaces (12) are rotated relative to one another about the bore axis (B) by a non-zero angle (α); the minor edge (24) further comprises an intermediate edge (28) between the two minor cutting edges (26); and in an end view, the two minor cutting edges (26) and the intermediate minor edge (28) formed on a common minor edge (24) are non-collinear; and (b) sintering the green body (10). 